U.S. patent number 5,642,084 [Application Number 08/259,568] was granted by the patent office on 1997-06-24 for dielectric filter having respective capacitance gaps flushed with the inner surface of corresponding holes.
This patent grant is currently assigned to Murata Manufacturing Co., Ltd.. Invention is credited to Hideyuki Kato, Yukihiro Kitaichi, Haruo Matsumoto, Hisashi Mori, Hitoshi Tada, Tatsuya Tsujiguchi, Yasuo Yamada, Tadahiro Yorita.
United States Patent |
5,642,084 |
Matsumoto , et al. |
June 24, 1997 |
Dielectric filter having respective capacitance gaps flushed with
the inner surface of corresponding holes
Abstract
A dielectric block having an external conductor on the outer
surface and a plurality of holes with internal conductors formed
therein; no internal conductors are provided near one end of each
of the plurality of holes. Portions of the dielectric block and the
external conductor are removed so as to obtain a dielectric
resonator having desired resonator characteristics. In another
embodiment, portions of the dielectric block are removed so as to
bring the external conductor closer to the internal conductors
thereby obtaining a dielectric resonator resonant with a desired
frequency. The dielectric resonators limit leakage of
electromagnetic field and do not require additional parts such as
terminals and case.
Inventors: |
Matsumoto; Haruo (Nagaokakyo,
JP), Yamada; Yasuo (Nagaokakyo, JP),
Kitaichi; Yukihiro (Nagaokakyo, JP), Yorita;
Tadahiro (Nagaokakyo, JP), Kato; Hideyuki
(Nagaokakyo, JP), Tsujiguchi; Tatsuya (Nagaokakyo,
JP), Mori; Hisashi (Nagaokakyo, JP), Tada;
Hitoshi (Nagaokakyo, JP) |
Assignee: |
Murata Manufacturing Co., Ltd.
(JP)
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Family
ID: |
26367201 |
Appl.
No.: |
08/259,568 |
Filed: |
June 14, 1994 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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09308 |
Jan 22, 1993 |
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Foreign Application Priority Data
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Jan 22, 1992 [JP] |
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4-009207 |
Apr 3, 1992 [JP] |
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4-029056 |
Oct 28, 1992 [JP] |
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4-312720 |
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Current U.S.
Class: |
333/202; 333/206;
333/207 |
Current CPC
Class: |
H01P
1/2056 (20130101); Y10T 29/49016 (20150115) |
Current International
Class: |
H01P
1/20 (20060101); H01P 1/205 (20060101); H01P
001/201 () |
Field of
Search: |
;333/202,206,203,207,222,223,235 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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0062202 |
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Apr 1985 |
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JP |
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0156902 |
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Jul 1986 |
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JP |
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62-040802 |
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Feb 1987 |
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JP |
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62-183603 |
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Aug 1987 |
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JP |
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258501 |
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Oct 1989 |
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JP |
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2163606 |
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Feb 1986 |
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GB |
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2240432 |
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Jul 1991 |
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GB |
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8302853 |
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Aug 1983 |
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WO |
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8500929 |
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Feb 1985 |
|
WO |
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Other References
Patent Abstracts of Japan, vol. 13, No. 522, (E-849) (3970),
Abstract No. 12-12001, Nov. 21, 1989. .
Patent Abstracts of Japan, vol. 11, No. 286 (E-541) (2733),
Abstract No. 62-85502, Sep. 16, 1987. .
Patent Abstracts of Japan, vol. 8, No. 256 (E-280) (1693), Abstract
No. 59-128801, Nov. 22, 1984. .
Patent Abstracts of Japan, vol. 6, No. 72, (E-106) (950), Abstract
No. 57-113801, May 7, 1982..
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Primary Examiner: Lee; Benny T.
Attorney, Agent or Firm: Ostrolenk, Faber, Gerb &
Soffen, LLP
Parent Case Text
This is a continuation application of Ser. No. 08/009,308, filed on
Jan. 22, 1993, now abandoned.
Claims
What is claimed is:
1. A dielectric filter with surface electromagnetic shielding,
comprising:
a dielectric body having an outer surface;
an external conductor substantially completely covering the outer
surface of the dielectric body so as to provide said surface
electromagnetic shielding of said dielectric filter; and
a plurality of holes extending through the dielectric body, each
hole having a respective inner surface with a substantially
constant cross-sectional shape along an axial direction of the
corresponding hole;
at least one hole of said plurality of boles having a respective
pair of internal conductors provided in the corresponding hole and
conductively connected to said external conductor at respective
ends of said corresponding hole, a respective non-conductive
portion at said inner surface of the corresponding hole being
spaced from both ends of said respective hole and thereby
separating said corresponding pair of internal conductors and
thereby defining a respective capacitance between said
corresponding pair of internal conductors, a surface of said
respective non-conductive portion being substantially flush with
the rest of said inner surface of the corresponding hole; and
signal input and output electrodes provided on the outer surface of
the dielectric body and electrically isolated from said external
conductor for providing capacitive coupling with respective
internal conductors of two of the plurality of holes, and closely
surrounded by said external conductor for providing capacitive
coupling with said external conductor.
2. The dielectric filter as claimed in claim 1, wherein the
dielectric body includes a side face, a recess being disposed in
the dielectric body at the side face, the external conductor
extending into the recess disposed in the dielectric body and over
a bottom surface of the recess.
3. The dielectric filter as claimed in claim 1, further comprising
at least one generally circular recess, disposed at a respective
location proximate to a corresponding one of said plurality of
holes, said at least one generally circular recess extending into
the dielectric body in generally the same direction as the
plurality of holes.
4. The dielectric filter as claimed in claim 1, wherein the
dielectric body includes a side face, at least one generally
circular recess being disposed in the dielectric body at the side
face, the external conductor extending into the generally at least
one circular recess in the dielectric body and over a respective
bottom surface of the corresponding recess, a portion of the
external conductor on the respective bottom surface of the at least
one generally circular recess being generally parallel to the
internal conductor in a corresponding one of the plurality of
holes.
5. The dielectric filter as claimed in claim 1, wherein the
dielectric body includes a side face, a recess being disposed in
the dielectric body at the side face.
6. The dielectric filter as claimed in claim 1, wherein the
dielectric body is a rectangular block, said outer surface of the
dielectric body defined by at least one face being adapted for
serving as a circuit base plate mounting face, the signal input and
output electrodes being provided on said at least one face of said
outer surface of the dielectric body.
7. The dielectric filter as claimed in claim 1, wherein at least
two said holes have a respective pair of internal conductors
separated by a corresponding non-conductive portion.
8. The dielectric filter as claimed in claim 7, wherein said
respective pair of non-conductive portions are spaced unequally
from the corresponding ends of the holes.
9. The dielectric filter as claimed in claim 8, wherein said
respective pair of non-conductive portions have unequal axial
lengths.
10. The dielectric filter as claimed in claim 7, wherein said
respective pair of non-conductive portions have unequal axial
lengths.
11. The dielectric filter as claimed in claim 1, wherein said outer
surface of the dielectric body defines a face and respective side
faces, the signal input and output electrodes are on the face of
said outer surface and extend from the face to said respective side
faces of the dielectric body.
12. The dielectric filter as claimed in claim 1, wherein the
dielectric body includes an end face, a pair of recesses being
desposed in the dielectric body at the end face thereby defining a
pair of side portions of the end face, the recesses being generally
parallel with the side portions and being located on respective
sides of the plurality of holes.
13. A dielectric filter with integral electromagnetic shielding,
comprising:
a dielectric body having an outer surface;
an external conductor substantially completely covering the outer
surface of the dielectric body so as to provide said integral
electromagnetic shielding of said dielectric filter; and
at least one hole extending through the dielectric body, said at
least one hole having a respective inner surface with a
substantially constant cross-sectional shape along an axial
direction of the corresponding hole;
said at least one hole having a respective pair of internal
conductors provided in the corresponding hole and conductively
connected to said external conductor at respective ends of said
corresponding hole, a respective non-conductive portion at said
inner surface of the corresponding hole being spaced from both ends
of said respective hole and thereby separating said corresponding
pair of internal conductors and thereby defining a respective
capacitance between said corresponding pair of internal conductors,
a surface of said respective non-conductive portion being
substantially flush with the rest of said inner surface of the
corresponding hole; and
signal input and output electrodes provided on the outer surface of
the dielectric body and electrically isolated from said external
conductor for providing capacitive coupling with at least one of
said internal conductors of said at least one hole, and closely
surrounded by said external conductor for providing capacitive
coupling with said external conductor.
Description
BACKGROUND OF THE INVENTION
The present invention generally relates to a dielectric resonator,
with an internal conductor which is formed within a dielectric, and
an external conductor which is formed on the outside face of the
dielectric, and a method for adjusting the characteristics of a
dielectric resonator.
A dielectric resonator, where a resonator electrode is formed
within a dielectric block and an earth electrode is formed on the
outside face of the dielectric block, and a so-called tri-plate
type of dielectric resonator with strip lines that are opposite to
each other by the use of a dielectric basic plate with a strip line
being formed on one main face and an earth electrode which is
formed on the other main face, are used as a band passing filter
and so on in, for example, the microwave band.
FIG. 39 shows as an exploded perspective view the construction of
the conventional general dielectric resonator using the dielectric
block. In FIG. 39, reference numeral 40 is a six-sided dielectric
block with three internal conductor shaped holes 46, 47, 48 having
an internal conductor provided therein and coupling holes 49, 50
which are provided among the internal conductor formed holes 46,
47, 48. The internal conductor is formed on the inside surface of
the internal conductor formed holes 46, 47, 48, and an external
conductor 51 is formed on five faces of the dielectric block 40
except for an open face 52. Reference numerals 53, 54 are so-called
resin pins, each being composed of resin portions 53a, 54a and
signal input, output terminals 53b, 54b. Two resin pins 53, 54 are
inserted into the internal conductor formed holes 46, 48 from the
open face side of the dielectric block 40 so that the terminals
53b, 54b are coupled in capacity to the internal conductor within
the internal conductor formed holes 46, 48. Reference numeral 55 is
a case for retaining the dielectric block 40 and the resin pins 53,
54 and also, for covering the open face portion of the dielectric
block 40. The resin pins 53, 54 are respectively inserted into the
dielectric block 40 so as to cover the case 55, and also, the whole
arrangement is integrated by soldering the dielectric block 40 with
the external conductor 51. In mounting the dielectric resonator,
the projecting portions 55a, 55b of the case 55 function as an
earth terminal.
As shown in FIG. 39, many of the components such as input, output
terminals 53b, 54b, case 55 and so on, are necessary if a plurality
of resonators are to be formed on a single dielectric block. The
assembling steps therefore become complicated. Moreover the
completed products, which have to be mounted as electronic
components, require that a lead wire attached to the component be
mounted in the mounting operation of the completed product on the
circuit basic plate. Therefore, the surface mounting operation
cannot be effected, as in other electronic components, so as to
mount these completed products on the same circuit basic plate, so
that a lower height operation is hard to effect. If the case 55 is
not used, by the direct connection of the external conductor 51 of
the dielectric block 40 to the earth electrode on the circuit basic
plate, the open face 52 is exposed, and, therefore, electromagnetic
field leakage is caused in this portion. When a metallic member
approaches toward the open face 52, the influences of the metallic
member are received. Also, the resonator is connected with
electromagnetic field from the outside so that the desired
characteristics of the dielectric resonator cannot be obtained.
SUMMARY OF THE INVENTION
Accordingly, the present invention has been developed with a view
to substantially eliminate the above discussed drawbacks that are
inherent in the prior art, and has for its essential object to
provide an improved dielectric resonator.
Another important object of the present invention is to provide an
improved dielectric resonator which can be surface mounted on the
circuit basic plate without the use of resin pins 53, 54 and a case
55 as individual parts, as required by the prior art device shown
in FIG. 39.
Still another object of the present invention is to provide a
dielectric resonator where electromagnetic field leakage between
the inside and the outside of the resonator near the opening
portion is restrained so as to remove the problem caused by the
above described electromagnetic field leakage.
A further object of the present invention is to provide a
characteristic adjusting method of a dielectric resonator capable
of adjusting the desired resonator characteristics with ease and
high accuracy.
A still further object of the present invention is to provide a
dielectric resonator in which it is easier to obtain floating
capacity by a comparatively simple working or molding
operation.
In accomplishing these and other objects, a dielectric resonator in
accordance with a first aspect of the invention is provided having
a portion of the internal conductor not formed near at least one
open face of the above described internal conductor formed holes,
and signal input, output electrodes for providing capacity
connection with the above described internal conductor are provided
on one portion of the outer conductor. The dielectric resonator
includes a plurality of internal conductor formed holes within the
dielectric block with the external conductor being formed on the
outside face of the above described dielectric block.
In the dielectric resonator of the first aspect of the invention,
the non-formed portion of the internal conductor is provided near
at least one open face of the internal conductor formed holes of
the dielectric resonator, and signal input, output electrodes for
effecting capacity connection with the internal conductor are
provided on one portion of the external conductor. A tip end
capacity is caused in the non-formed portion of the internal
conductor in the internal conductor formed hole so as to provide
column-in coupling or interdigital connection between the adjacent
resonators. In this construction, the conductor is not removed from
the open face of the internal conductor formed holes, so that large
electromagnetic field leakage is not caused. As the coupling holes
are not required, the whole arrangement can be easily made smaller
in size. As the signal input, output electrodes are provided in one
portion of the external conductor so as to provide a capacity
connection with the internal conductor, the signal input, output
terminals as separate, individual parts are not required. The
external conductor is connected with the earth electrode on the
circuit basic plate by the surface mounting operation on the
circuit basic plate, and also, the signal input, output electrodes
can be similarly connected with the signal line on the circuit
basic plate.
A dielectric resonator of a second aspect of the invention
described in accordance with the first aspect of the invention is
characterized in that the above described dielectric resonator is
an approximately six-face unit in shape so as to form the above
described signal input, output electrodes only on the circuit basic
plate mounting face.
In the dielectric resonator of the second aspect of the invention,
the above described signal input, output electrodes are formed only
on the mounting face with respect to the circuit basic plate.
Therefore, electromagnetic field leakage of the signal input,
output electrodes is reduced with the dielectric resonator being
mounted on the circuit basic plate, changes in the resonator
characteristics by the influences of the metallic member and so on
of the peripheral portion are less, and unnecessary connection with
the other circuit portion is not required thereby simplifying the
circuit designing operation. Further, the pattern formation is
simplified, because the signal input, output electrodes have only
to be formed within one plane.
A dielectric resonator of a third aspect of the invention, where a
plurality of internal conductor formed holes within the dielectric
are provided, an external conductor is formed on the outside face
of the above described dielectric resonator, one open face of the
above described internal conductor formed holes is made a
short-circuit face, and also, a non-formed portion of the internal
conductor is provided near the other open face, signal input,
output electrodes for providing capacity connection with the above
described internal conductor are provided on one portion of the
external conductor, and portions of the conductor and the
dielectric are removed from one portion of the above described
short-circuit face, the above described other open face, or both
the faces.
In the dielectric resonator of the third aspect of the invention,
one open face of the above described internal conductor formed
holes is made a short-circuit face, and also, a non-formed portion
of the internal conductor is provided near the other open face,
signal input, output electrodes for providing capacity connection
with the above described internal conductor are provided on one
portion of the external conductor, and portions of the conductor
and the dielectric are not formed in one portion of the open face
where the non-formed portion of the internal conductor is provided,
or the short-circuit face, or both the faces. If portions of the
conductor and the dielectric are deleted in the open face where the
non-formed portion of the internal conductor is provided, the
resonance frequency of the resonator can be raised. If the
conductor and the dielectric between the open portions of adjacent
internal conductor formed holes in the short circuit face are
deleted, the coupling between the resonators is weakened and also,
the resonance frequency of the resonator can be lowered. If the
conductor and the dielectric around the internal conductor formed
holes except for between the open portions of the adjacent internal
conductor formed holes are deleted, the resonance frequency of the
resonator can be lowered. Therefore, the coupling adjusting and the
frequency adjustment can be easily effected without coating
addition and so on of the conductor on the non-formed portion of
the conductor.
A dielectric resonator of a fourth aspect of the invention where
internal conductor formed holes with an internal conductor being
formed on the inside surface are provided on the dielectric, and an
external conductor is provided on the outside face of the
dielectric, characterized in that hollows are formed near the
internal conductor formed holes in at least one open face of the
internal conductor formed holes so as to delete the internal
conductor near the above described hollow formed portions.
In the dielectric resonator of the fourth aspect of the invention,
hollows with an internal conductor formed hole as a center are
formed on at least one open face of the internal conductor formed
holes of the dielectric resonator, and the internal conductor near
the hollow formed holes is deleted. The open portion of the
internal conductor is formed in a location secluded from the
opening face. The open portion of the internal conductor is
provided on the inside away from the open face of the internal
conductor formed holes, and electromagnetic field leakage between
the inside and the outside of the dielectric resonator is lessened
so that stable resonator characteristics are obtained.
A dielectric resonator of a fifth aspect of the invention where
internal conductor formed holes with an internal conductor being
formed on the inside face thereof are provided in the dielectric,
and the external conductor is formed on the outside face of the
dielectric, one portion of the internal conductor is deleted near
the open face of the internal conductor formed holes and in a
location secluded from the open face.
In the dielectric resonator of the fifth aspect of the invention,
one portion of the internal conductor is deleted near the open face
of the internal conductor formed holes and in the location secluded
from the open face. As the open portion of the internal conductor
is formed in the location secluded from the open face of the
resonator, the electromagnetic field leakage is prevented.
A dielectric resonator of a sixth aspect of the invention where
internal conductor formed holes with an internal conductor being
formed on the inside face are provided in the dielectric, and
external conductors are formed on the outside face of the
dielectric, characterized in that a throttle portion is formed in
at least one open portion of the internal conductor formed holes,
and the internal conductor is deleted near the throttle portion and
on the internal conductor formed hole side.
In the dielectric resonator of the sixth aspect of the invention, a
throttle portion is formed on at least one open face of the
internal conductor formed holes, and the internal conductor is
deleted near the throttle portion and on the internal conductor
formed hole side. Accordingly, the open portion of the internal
conductor is formed in a location secluded from the open face of
the internal conductor formed holes so as to prevent the
electromagnetic field leakage.
A dielectric resonator of a seventh aspect of the invention where
internal conductor formed holes with an internal conductor being
formed in the inside face are provided in the dielectric, and the
external conductor is formed on the outside face of the dielectric,
a throttle portion is formed in a location near one open face of
the internal conductor formed holes and secluded from the open face
so as to delete the internal conductor of the above described
throttle portion.
In a dielectric resonator of the seventh aspect of the invention, a
throttle portion is formed in a location near one open face of the
internal conductor formed holes and secluded from the open face so
as to delete the internal conductor of the above described throttle
portion. Therefore, as the open portion of the internal conductor
is formed in a location secluded from the open face of the internal
conductor formed holes, the electromagnetic field leakage is
prevented.
A dielectric resonator of an eighth aspect of the invention is made
resonant with a desired frequency by forming the inside conductor
on the inside face of a hole in the dielectric, and forming the
outside conductor on the outside face of the above described
dielectric; a concave portion is formed on the surface of the above
described dielectric so as to cause the outside conductor in the
bottom portion of the concave portion to approach the above
described inside conductor.
In the eighth aspect of the invention, the outside conductor at the
bottom portion of the concave portion formed on the surface of the
dielectric is brought towards the above described inside conductor,
the interval between the inside conductor of the hole of the
dielectric and the outside conductor, which becomes an earth
electrode, becomes smaller, and floating capacity is likely to be
obtained. The floating capacity can be adjusted by a comparatively
simple working or molding operation of the size, depth and so on of
the concave portion. In the comb-line type resonator, the band
width of the filter can be made larger by provision of, for
example, larger floating capacity. The resonator length becomes
shorter, and the size can be made smaller by the provision of, for
example, larger floating capacity.
A dielectric resonator of a ninth aspect of the invention where a
taper portion is formed on a corner portion of the dielectric so as
to cause the outside conductor of the taper portion to approach
toward the inside conductor.
In the ninth aspect of the invention, the taper portion is formed
on a corner portion of the dielectric so as to cause the outside
conductor at the taper portion to approach toward the inside
conductor, so that the distance between the inside conductor of the
hole in the interior of the dielectric and the outside conductor,
which becomes an earth electrode is reduced, and floating capacity
is likely to be obtained as in the previous aspect of the
invention. The floating capacity can be adjusted by a comparatively
simple working or molding operation of the size, inclination and so
on of the taper portion in the corner portion of the dielectric. In
the comb-line type resonator, the band width of the filter may be
made larger by the provision of, for example, larger floating
capacity. The resonator length becomes shorter and the size become
smaller by the provision of, for example, the larger floating
capacity.
A dielectric resonator of a tenth aspect of the invention where a
concave stage portion of approximately L type (in section) is
provided in a corner portion of the dielectric so as to cause the
outside conductor of the concave stage portion to approach toward
the inside conductor.
In the tenth aspect of the invention, a concave stage portion of
approximately L type (in section) is provided in the corner portion
of the dielectric so as to cause the outside conductor at the
concave stage portion to approach toward the inside conductor, so
that the distance between the inside conductor of the hole in the
interior of the dielectric and the outside conductor, which becomes
an earth electrode, becomes shorter, and floating capacity is
likely to be obtained. The floating capacity can be adjusted by a
comparatively simple working or molding operation of the size,
depth and so on of the concave stage portion in the corner portion
of the dielectric. In the comb-line type resonator, the band width
of the filter may be made larger by the provision of, for example,
larger floating capacity. The resonator length becomes shorter and
the size becomes smaller by the provision of, for example, the
larger floating capacity.
A characteristic adjusting method of a dielectric resonator of an
eleventh aspect of the invention, where internal conductor formed
holes with an internal conductor formed on the inside face therein
the external conductor being formed on the outside face of the
dielectric, comprising the steps of deleting the internal conductor
near the above described hollow formed portion, adjusting the tip
end capacity of the internal conductor with a hollow that is formed
near the internal conductor formed hole in at least one open face
of the above described internal conductor formed holes.
In the characteristic adjusting method of the dielectric resonator
of the eleventh aspect of the invention, a hollow is initially
formed, with the opening of the internal conductor formed hole
being provided as a center, on at least one open face of the
internal conductor formed holes, and the internal conductor near
the hollow formed portion is deleted. The internal edge portion of
the internal conductor formed hole opening portion is not deleted
by the deletion of the internal conductor near the hollow formed
portion. One portion of the internal conductor and the dielectric
can be deleted with high accuracy. As a result, the desired
resonator characteristics can be obtained with ease and in a short
time by the adjustment of the resonator characteristics to high
accuracy.
A characteristic adjusting method of a dielectric resonator of a
twelfth aspect of the invention where an internal conductor formed
hole with an internal conductor being formed on the inside face is
provided in the dielectric and the external conductor is formed on
the outside face of the dielectric, comprising the steps of
initially forming a throttle portion on one open face of the above
described internal conductor formed hole, deleting the internal
conductor formed on the above described throttle portion, adjusting
the tip end capacity of the internal conductor.
In a characteristic adjusting method of a dielectric resonator of
the twelfth aspect of the invention, a throttle portion is
initially formed on one open portion of the internal conductor
formed hole, the tip end capacity of the internal conductor is
adjusted by the deletion of the internal conductor formed on the
throttle portion. As the internal conductor and the dielectric are
deleted only in the throttled portion, in the deleting operation of
the internal conductor formed initially on the throttled portion,
the adjustment can be carried out with high accuracy.
A characteristic adjusting method of a dielectric resonator of a
thirteenth aspect of the invention where internal conductor formed
holes with an internal conductor being formed on the inside face
are provided in the dielectric and the external conductor is formed
on the outside face of the dielectric, comprising the steps of
initially forming a throttle portion in a location near one open
face of the above described conductor formed holes and secluded
from the open face, deleting the internal conductor formed on the
above described throttle portion, and adjusting the tip end
capacity of the internal conductor.
In a characteristic adjusting method of the thirteenth aspect of
the invention, a throttle portion is initially formed in a location
near one open face of the internal conductor formed holes and
secluded from the open face, the internal conductor formed on the
throttle portion is deleted, and the tip end capacity of the
internal conductor is adjusted in this manner. The adjusting
operation can be carried out with high accuracy so as to delete the
internal conductor initially formed on the throttle portion.
BRIEF DESCRIPTION OF THE DRAWINGS
These and other objects and features of the present invention will
become apparent from the following description taken in conjunction
with the preferred embodiment thereof with reference to the
accompanying drawings, in which;
FIG. 1 is a perspective view of a dielectric resonator which is
made in accordance with a first embodiment;
FIG. 2 is a sectional view of the dielectric resonator which is
made in accordance with the first embodiment;
FIG. 3 is a sectional view of a dielectric resonator in accordance
with the first embodiment after deletion of a portion of the inner
conductor;
FIG. 4 is a perspective view of a dielectric resonator in
accordance with the first embodiment after deletion of a portion of
the inner conductor;
FIG. 5 is an exploded perspective view of the dielectric resonator
in accordance with the first embodiment;
FIG. 6 is an equivalent circuit diagram of the dielectric resonator
in accordance with the first embodiment;
FIGS. 7A and B show the construction of a dielectric resonator in
accordance with a second embodiment; (A) is a horizontal sectional
view and (B) is a front face view;
FIG. 8 is a front face view of a dielectric resonator in accordance
with a third embodiment;
FIG. 9 is a front face view showing a conductor deleted embodiment
for the characteristics measurement of the dielectric resonator in
accordance with the third embodiment;
FIG. 10 is a partial front face view showing the conductor deleted
embodiment for the characteristics measurement of the dielectric
resonator in accordance with the third embodiment;
FIG. 11 is a graph showing the measurement result in the coupling
coefficient changes of the dielectric resonator in accordance with
the third embodiment;
FIG. 12 is a graph showing the measurement result in the resonance
frequency changes of the dielectric resonator in accordance with
the third embodiment;
FIG. 13 is a front face view of a dielectric resonator in
accordance with a fourth embodiment;
FIG. 14 is a perspective view of a dielectric resonator in
accordance with a fifth embodiment;
FIG. 15 is an exploded perspective view of a dielectric resonator
in accordance with a sixth embodiment;
FIG. 16 is a perspective view of the dielectric resonator in
accordance with the sixth embodiment;
FIG. 17 is a sectional view of the dielectric resonator in
accordance with the sixth embodiment;
FIG. 18 is another sectional view of the dielectric resonator in
accordance with the sixth embodiment;
FIG. 19 is yet another sectional view of the dielectric resonator
in accordance with the sixth embodiment;
FIG. 20 is a sectional view of a dielectric resonator in accordance
with a seventh embodiment;
FIG. 21 is a sectional view of a dielectric resonator in accordance
with an eighth embodiment;
FIG. 22 is a sectional view of the dielectric resonator in
accordance with the eighth embodiment;
FIG. 23 is a view showing the shape of a grindstone;
FIG. 24 is a view showing the shape of another grindstone;
FIG. 25 is a perspective view of one dielectric basic plate for
constituting the dielectric resonator in accordance with a ninth
embodiment;
FIG. 26 is a sectional view of the dielectric resonator of the
ninth embodiment;
FIG. 27 is a sectional view of the dielectric resonator in
accordance with the ninth embodiment;
FIGS. 28 (a) and (b) are a perspective view and a sectional view
respectively, of a dielectric resonator in a tenth embodiment of
the present invention;
FIG. 29 is a perspective view of a dielectric resonator of an
eleventh embodiment of the present invention;
FIGS. 30 (a) and (b) are a perspective view and an essential
portion sectional view, respectively of a dielectric resonator of a
twelfth embodiment;
FIGS. 31 (a) and (b) are a perspective view and an essential
portion sectional view, respectively of a dielectric resonator of a
thirteenth embodiment;
FIGS. 32 (a) and (b) are a perspective view and an essential
portion sectional view, respectively of a dielectric resonator of a
fourteenth embodiment;
FIGS. 33 (a) and (b) are a perspective view and an essential
portion sectional view, respectively of a dielectric resonator of a
fifteenth embodiment of the present invention;
FIG. 34 is a perspective view of a dielectric resonator of a
sixteenth embodiment thereof;
FIG. 35 is a perspective view of a dielectric resonator of a
seventeenth embodiment thereof;
FIG. 36 is a perspective view of a dielectric resonator of an
eighteenth embodiment of the present invention;
FIG. 37 is a perspective view of a dielectric resonator of a
nineteenth embodiment thereof;
FIG. 38 is a sectional view of a dielectric resonator of a
twentieth embodiment thereof; and
FIG. 39 is an exploded perspective view of a conventional
dielectric resonator.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENT OF THE INVENTION
Before the description of the preferred embodiment of the present
invention proceeds, it is to be noted that like parts are
designated by like reference numerals throughout the accompanying
drawings.
(First Embodiment)
The construction of a dielectric resonator and a characteristic
adjusting method thereof in a first embodiment of the present
invention will be described hereinafter in accordance with FIG. 1
through FIG. 6.
FIG. 1 is a perspective view of a dielectric resonator. In FIG. 1,
reference numerals 5, 6 are holes having an internal conductor
provided therein, hereinafter referred to as internal conductor
formed holes. The internal conductor formed holes 5, 6 are formed
in a dielectric block having generally six sides. The internal
conductor is formed in advance on the inside surfaces of the
internal conductor formed holes 5, 6. An external conductor 4 is
formed on all the outside faces (six faces) of the dielectric
block. Signal input, output electrodes, shown by reference numerals
9, 10, are formed in the respective portions of the external
conductor 4, as shown in FIG. 1.
FIG. 2 is a vertical sectional view passing through the internal
conductor formed hole 6 in FIG. 1. An internal conductor, shown by
reference numeral 3 is formed on the entire inside face of the
internal conductor formed hole 6. A non-formed portion (hereinafter
referred to as an open portion) of the inner conductor is provided
in one portion of the internal conductor when a dielectric
resonator having desired resonating characteristics is to be
obtained from such a dielectric block. As shown in FIG. 3, the
internal conductor near one opening of the internal conductor
formed holes 5, 6 is not formed so as to adjust the resonance
frequency and the coupling degree of the dielectric resonator. FIG.
4 is a perspective view showing a dielectric resonator after the
open portion is formed. FIG. 3 is a vertical sectional view
thereof. In FIG. 3, a portion is made an open portion by the
internal conductor near the opening of the internal conductor
formed hole, shown with the letters A, B being deleted. FIG. 5 is a
view where the dielectric resonator shown in FIG. 4 is cut and
separated with the central horizontal face having the signal input,
output electrodes 9, 10 facing downward. A tip end capacity Cs is
caused, between the tip end portion of the internal conductor 2 and
the external conductor 4, in the open portion of, for example, the
internal conductor 2, and an external coupling capacity Ce is
caused between the tip end portion vicinity of the internal
conductor 2 and the signal input, output electrode 9. The tip end
capacity is adjusted by a size S, shown in FIG. 3, of the open
portion thereby adjusting the coupling degree between the resonance
frequency of the resonator and the resonator.
FIG. 6 is an equivalent circuit diagram of the dielectric resonator
shown in FIG. 1 through FIG. 5. In FIG. 6, reference character R1
is a resonator with the internal conductor 2, reference character
R2 is a resonator with the internal conductor 3. Reference
character Cs is a tip end capacity that is formed in the open
portion of the respective internal conductors 2, 3. Reference
character Ce is an external coupling capacity that is formed
between the signal input, output electrodes 9, 10 and the open
portions of the internal conductors 2, 3.
(Second Embodiment)
The construction of a dielectric resonator in a second embodiment,
which is different in the position of the open portion formed
within the internal conductor formed hole, is shown in FIG. 7. FIG.
7A is a central horizontal sectional view of a dielectric block
FIG. 7B is a front face view seen from the short-circuit face side
of the dielectric block. The open portions of the internal
conductors 2, 3, which are provided within the internal conductor
formed holes 5, 6 are situated in locations spaced away from the
openings of the internal conductor formed holes 5, 6 so as to form
the tip end capacity Cs in the open portions. Thus, electromagnetic
field leakage can be further prevented.
(Third Embodiment)
The construction of a dielectric resonator in accordance with a
third embodiment where the resonance frequency and the coupling
degree have been adjusted by the provision of a non-formed portion
of the conductor and the dielectric in one portion of the
short-circuit face, is shown in FIG. 8. FIG. 8 is a front face view
seen from the short-circuit face side, with reference characters C,
D being non-formed portions of the conductor and the dielectric of
the short-circuit face. The resonance frequency of the resonator by
the internal conductor formed hole 5 is lowered by the partial
deletion of the conductor and the dielectric in the region of SI in
FIG. 8. Similarly, if the conductor and the dielectric are
partially deleted in the region of S2, the resonance frequency of
the resonator is lowered by the internal conductor formed hole 6.
The coupling degree between both the resonators is lowered if the
conductor and the dielectric are partially deleted in the region of
S12. Modified embodiments of the coupling coefficients by the
deletion of the conductor and the dielectric are shown in FIG. 9
and FIG. 11. A conductor deletion portion of a width d is provided
in a middle position from the two coupling holes, as shown in FIG.
9. Changes in the coupling coefficients are measured when the
conductor deletion area S is changed. In FIG. 9, a=2.0 mm, b=4.0
mm, c=5.0 mm. FIG. 11 shows the change ratio of the coupling
coefficients with the axis of abscissas being a conductor deletion
area S, and the axis of ordinates being the ratio of change in the
coupling coefficients with Ko the coupling coefficient in the case
of S=0 and Ka the coupling coefficient after the conductor
deletion. The coupling coefficient can be adjusted by adjusting the
conductor deletion area among the internal conductor formed holes
on the short-circuit face. FIG. 10 and FIG. 11 show an adjustment
example of the resonance frequency. A conductor deletion portion of
a length g with a width f is provided, in a location spaced away at
a given distance from the internal conductor formed hole, as shown
in FIG. 10, so as to measure the resonance frequency when the
length g is changed. In FIG. 10, a=2.0 mm, e=3.0 mm, f=0.5 mm. In
FIG. 12, the axis of abscissas is the length g of the conductor
deletion portion, and the axis of ordinates shows the variation
amount in the resonance frequency with the resonance frequency in
the case of g=0 being a reference. Accordingly, the resonance
frequency can be adjusted by adjusting the conductor deletion
portion of the internal conductor formed periphery on the
short-circuit face.
(Fourth Embodiment)
A fourth embodiment, also shown in FIG. 8 through FIG. 12 and
further in FIG. 13 is that portions of the conductor and the
dielectric are deleted on the short-circuit face, and the capacity
Cs is thereby decreased. Moreover, the conductor and the dielectric
on the other face, on the internal conductor non-formed portion
side, are also deleted, so that the resonance frequency can be
adjusted in a higher direction.
Although two stages of dielectric resonator are shown in the
examples shown in FIG. 8 through FIG. 12, the same features can be
applied even to a dielectric resonator of three stages or more. The
coupling degree between the resonators are adjusted by the partial
deletion of the conductor and the dielectric in the areas S12, S23,
. . . S.sub.n-1 n among the openings of the internal conductor
formed holes on the short-circuit face as shown in FIG. 13. The
resonance frequency of the respective resonators can be adjusted by
the partial deletion of the conductor and the dielectric in the
regions of S1, S2, S3 . . . Sn, shown in FIG. 13.
(Fifth Embodiment)
The construction of a dielectric resonator in a fifth embodiment,
which is different in the shape of the signal input, output
electrodes, is shown in FIG. 14, which is a perspective view. In
FIG. 14, reference numerals 16, 17, 18 are internal conductor
formed holes with the internal conductor and the open portions
thereof being formed on the inside surfaces of the holes 16, 17,
18. External conductor 4 is provided on the outside face of the
dielectric block, with the signal input, output electrodes 9, 10
being formed only on the top face as shown in the drawing. The
electrode 9 is coupled in capacity to the internal conductor within
the internal conductor formed hole 16, and the electrode 10 is
coupled in capacity to the internal conductor within the internal
conductor formed hole 18. When the dielectric resonator is mounted
on a circuit basic plate, the top face as shown in the drawing is
positioned so as to be opposed to the mounting surface of the
circuit basic plate.
(Sixth Embodiment)
The construction of a dielectric resonator and its characteristic
adjusting method thereof in accordance with a sixth embodiment will
be described hereinafter with reference to FIG. 15 through FIG.
19.
FIG. 15 is an exploded perspective view of the dielectric
resonator. In FIG. 15, reference numerals 1a, 1b are, respectively,
dielectric basic plates. Two semicircular grooves are formed,
respectively, on one main face of each dielectric basic plates 1a,
1b and the internal conductor is formed on inside faces thereof.
Reference numerals 2b, 3b are internal conductors provided on the
inside of the grooves of the dielectric basic plate 1b. Hollowed
out portions or hollows 7a, 8a and 7b, 8b are formed at ends of the
grooves of the dielectric basic plates 1a, 1b, respectively. An
external conductor 4a is provided on the other main face, opposite
to the internal conductor formed main face, and the four side faces
of the dielectric basic plate 1a and an external conductor 4b is
similarly provided on the other main face, opposite to the internal
conductor formed face, and the four side faces of the dielectric
basic plate 1b. Signal input, output electrodes 9, 10 are formed in
the external conductor 4a of the dielectric basic plate 1a, as
shown in FIG. 15.
FIG. 16 shows a dielectric resonator before characteristic
adjustment, with the two dielectric basic plates 1a, 1b, shown in
FIG. 15, being connected with the internal conductors formed
therein placed in opposing positions to each other. Circular shaped
internal conductor formed holes 5, 6 are constructed by the
combination of the semi-circular shaped grooves shown in FIG. 15.
The step shaped hollows 7, 8 shown are constructed by the
combination of the hollows 7a, 7b and 8a, 8b formed on the
dielectric basic plates 1a, 1b. The dielectric resonator, shown in
FIG. 16, is mounted after characteristic adjustment with the top
face shown in the drawing being in contact against the basic
plate.
FIG. 17 is a sectional view through the internal conductor formed
hole 6 of the dielectric resonator shown in FIG. 16.
Lines on the connection face of the dielectric basic plate have
been omitted (the views for reference are also the same in the
subsequent description) so as to avoid complicated views.
FIG. 18 and FIG. 19 are two embodiments where an open portion is
formed in one portion of the internal conductor and the resonator
characteristics are thereby adjusted. In FIG. 18, reference
character A shows locations where the respective one-portions of
internal conductors 3a, 3b are deleted near the hollow formed
portions. More specifically, grinding tools such as Ryta with a
grindstone, shaped as shown by reference numeral 11, being mounted
thereon are used. The deleted portion is made into an open portion
with one portion of the internal conductor being removed by the use
of the grinding tool. As the deleted portion A of the internal
conductor is formed in a location spaced away from the open face F
as shown in FIG. 18, electromagnetic field leakage is prevented
with respect to the interior from the open face F and the resonator
is hardly influenced by electromagnetic field at the resonator
periphery. If a metallic unit is located near the open face F, the
characteristics of the resonator are not disturbed by influences
from the metallic unit. When the adjusting operation is conducted
with the use of a grinding tool as shown in FIG. 18, the amount of
the internal conductors 3a, 3b removed is controlled by the
insertion depth of the grinding tool so that the tip end capacity
can be easily adjusted. As the resonator frequency and the coupling
degree of its adjacent resonators change if the tip end capacity
changes, the desired resonator characteristics are obtained by
adjusting the insertion depth of the grinding tool with respect to
the internal conductor formed hole. As shown in FIG. 18, the tip
end capacity, which is to be formed in the open portion of the
internal conductor, is large so that the coupling degree between
the resonators is made large so as to easily make the band
broader.
FIG. 19 shows an other adjustment characteristic method. In FIG.
19, reference character B shows locations where the dielectric has
been removed together with the internal conductor near the hollow
portion formed near one opening of the internal conductor formed
hole 6. A grinding tool 11, which is provided with a grindstone
having a scoop diameter larger than the inside diameter of the
internal conductor formed hole, is used so as to grind the
dielectric together with the internal conductor. Accordingly, the
grinding tool is inserted in an axial direction from the hollow
formed portion with the grinding tool being set to the center of
the bore of the internal conductor formed hole so that the
dielectric together with the internal conductor can be easily
ground and removed by a fixed amount.
(Seventh Embodiment)
FIG. 20 shows a sectional view of a dielectric resonator in
accordance with a seventh embodiment. In FIG. 20, reference
characters A, B show the locations of deleted portion of the
internal conductors. One portion of the internal conductor is
ground, near the opening of the internal conductor formed hole, in
a location spaced away from the opening face, so that the open
portion of the internal conductor is formed at a location spaced
away from the open face of the dielectric resonator. Accordingly,
the problem caused by electromagnetic field leakage is removed. A
grinding tool, provided with a grindstone of comparatively small
diameter, is used for formation and adjustment of such an open
portion so that an inserting operation and a boring operation can
be effected obliquely from the open portion. At this time, one
portion of the dielectric is also ground, as shown by letter B in
FIG. 20 and the tip end capacity can be adjusted by the depth
thereof.
(Eighth Embodiment)
The construction of a dielectric resonator and its characteristic
adjusting method in an eighth embodiment will be described
hereinafter in accordance with FIG. 21 and FIG. 22.
FIG. 21 is a sectional view through an internal conductor formed
hole portion of the dielectric resonator. The basic construction is
different from the sixth embodiment although it is almost similar
to the construction of FIG. 15 and FIG. 16. A narrowed throttle
portion 13 is formed at one opening of the internal conductor
formed hole. Internal conductors 3a, 3b are formed on the inside
surface of the internal conductor formed hole and external
conductors 4a, 4b are provided on the outside surface of the
dielectric resonator, as shown in FIG. 21. A conductor film, which
is continuous to the external conductor from the internal
conductor, is formed on the inside surface of the throttle portion
13.
FIG. 22 is a view showing an example of the formation of an open
portion and an adjusting method. In FIG. 22, reference character A
shows the locations of the deleted portions of the internal
conductor and the dielectric. One portion of the internal conductor
is deleted on the internal conductor formed hole side of the
throttled portion 13 whereby the open portion of the internal
conductor is formed in a location spaced away from the open face.
Therefore, electromagnetic field leakage is restrained. In order to
form such an open portion, so as to effect the characteristic
adjustment, a grindstone of Ryta is inserted from an opening of the
internal conductor formed hole where the throttle portion 13 is not
formed into the internal conductor formed hole so as to adjust the
grinding amount by the insertion depth thereof, as shown in FIG.
22. The change proportion of change of the tip end capacity with
respect to the insertion amount of the grindstone is dependent on
the tip end shape of the grindstone. A grindstone shaped as shown
in FIG. 23 and FIG. 24 may be used considering the desired and
accuracy of the characteristic adjustment.
(Ninth Embodiment)
The construction and adjustment method of a dielectric resonator in
accordance with a ninth embodiment will be described hereinafter in
accordance with FIG. 25 through FIG. 27.
FIG. 25 shows one basic plate for forming a dielectric resonator.
In FIG. 25, reference character 1b is a dielectric basic plate. Two
semicircular (sectional) grooves are formed on one main face of the
dielectric basic plate 1b with internal conductors 2b, 3b being
formed on the inside faces thereof. Semicircular sectional portions
14b, 15b of the throttle portion are formed in one portion of each
groove. An external conductor 4b is formed on the other main face,
opposite to the internal conductor, and the four side faces of the
dielectric basic plate 1b. A dielectric resonator is formed with
two basic plates, which are shaped the same as the basic plate
shown in FIG. 25 being connected opposite to each other.
FIG. 26 is a sectional view thereof. In FIG. 26, reference numerals
15a, 15b indicate a throttle portion formed in one portion of the
internal conductor formed hole. In a dielectric resonator having
such a narrower or throttle portion in one portion of an internal
conductor formed hole, an internal conductor formed on the inside
surface of the throttle portion is removed with the use of a
grinding tool or the like, near one opening of the internal
conductor formed hole, as shown in FIG. 27, so as to form an open
portion in the internal conductor and effect a characteristic
adjustment. In FIG. 27, reference character A shows the deleted
portions hereof. In this manner, electromagnetic field leakage is
restrained by forming the open portion of the internal conductor in
a location spaced away from the open face of the dielectric
resonator. The adjusting operation is simplified, and the adjusting
accuracy is also improved, as the grinding range for the grinding
tool is restricted to the throttle portion. Although the sixth
through the ninth embodiments each have two dielectric basic plates
superposed in the embodiment, the construction and the
characteristic adjustment method of the sixth through the ninth
embodiment can be applied in the same manner even to an integral
type dielectric resonator with an internal conductor formed hole
being provided in a single dielectric block as in the first through
the fifth embodiments. The construction and characteristic
adjustment method of the first through the fifth embodiments can
have two dielectric basic plates superposed as in the sixth through
the ninth embodiments, and can be applied in the same manner even
to the dielectric resonator with the internal conductor formed
holes being provided therein.
Although the present embodiments have a comb line-type of
dielectric resonator as an example, even an interdigital type can
be similarly applied.
(Tenth Embodiment)
FIG. 28 (a) shows a tenth embodiment. Slot-like portions 28 are
formed in the dielectric body with the inside of the slots being
approximately parallel with the end face 22a side of the dielectric
22. The portions 28 are formed on both the sides of the holes 23
which have an inside conductor 24 of the dielectric 22 formed on
the inside surface. An outside conductor 25 is formed across the
entire outside surface of the dielectric 22, including the slot
portion 28. Accordingly, the distance between the outside conductor
25, which becomes an earth electrode for the bottom portions of the
slot portions 28, and the inside conductor 24 becomes shorter as
shown in FIG. 28 (b), so that floating capacity Cs can be easily
obtained.
The slot portion 28 can be worked into the dielectric 22 or formed
in it by a molding operation. Accordingly, the floating capacity Cs
can be obtained by a comparatively simple working operation or the
molding operation. The adjustment of the floating capacity Cs (size
of the floating capacity Cs) can be easily effected by variation of
the size and the depth of the slot portion 28 or by removing one
portion of the outside conductor 25.
In the comb-line type filter, the band width of the filter can be
made larger by provision of, for example, a larger floating
capacity Cs. The resonator length becomes shorter and the size can
be made smaller by provision of, for example, the larger floating
capacity Cs. Further, the floating capacity Cs can be easily
obtained, and also, the adjustment of the floating capacity Cs can
be easily effected even in a filter having the construction of
interdigital coupling.
(Eleventh Embodiment)
FIG. 29 shows an eleventh embodiment, which is different from the
previous embodiment, with a single slot-like portion 28 being
provided on one side of the dielectric 22. Even in this embodiment,
the floating capacity Cs can be easily obtained and the adjustment
can be easily effected as in the previous embodiment.
(Twelfth Embodiment)
FIGS. 30 (a) and (b) show a twelfth embodiment. In this embodiment,
the slot-like portion 28 is formed on one side face of the
dielectric 22. The external conductor 25 at the bottom portion of
the slot portion 28 is brought towards the inside conductor 24,
which is formed within the hole 23 of the dielectric 22, so as to
easily obtain the floating capacity Cs.
The interval t between the outside conductor 25, which becomes an
earth electrode and the inside conductor 24, the width w and the
depth d of the slot portion 28 and so on may be changed so as to
control the floating capacity Cs.
The coupling between the resonators can be adjusted by the
adjustment of the floating capacity Cs. The passing zone of the
filter can be controlled without changes. The above described
floating capacity Cs can be made larger by adjusting the slot
portion 28.
The shape of the dielectric resonator can be standardized, the
metal mold cost and the management cost can be reduced. In the
embodiment shown in FIGS. 30 (a) and (b), the slot portion 28,
which is formed on one side face of the dielectric 22, may be
formed on both the side faces of the dielectric 22. In this case,
the floating capacity Cs can be made even.
(Thirteenth Embodiment)
FIGS. 31 (a) and (b) show a thirteenth embodiment. Round hole
shaped portions 28 are formed, in the same direction, near the
holes 23. The hole portions 28 are respectively formed in
accordance with the number of holes 23. The number of hole portions
28 formed may be one, or the hole portions 28 may be formed
according to the number of the holes 23 or more. The hole portions
28 may be provided correspondingly on both the sides of the holes
23. Many hole portions 28 may be formed.
(Fourteenth Embodiment)
FIGS. 32 (a) and (b) show a fourteenth embodiment. In this
embodiment, the round hole shaped portions 28 are formed on the
side face of the dielectric 22. The external conductor 25 at the
bottom portion of the hole portions 28 is brought near in parallel
to the internal conductor 24. Even in this embodiment, the hole
portions 28 are formed so as to correspond to the holes 23. The
number of the hole portions 28 may be one or may be three or more.
In addition, the hole portions 28 may be formed in either face of
the dielectric 22.
(Fifteenth Embodiment)
FIGS. 33 (a) and (b) show a fifteenth embodiment. Slope-like or
taper potions 29 are formed on both the corner portions of the open
face 23 of the dielectric 22, as shown in FIG. 33 (a). The taper
portions 29 are formed so that the distance between the internal
conductor 24, within the hole 23, and the external conductor 25,
which serves as an earth electrode of the taper portions 29 is
reduced, and the floating capacity Cs can therefore be easily
obtained as in the above described embodiments.
The size of the floating capacity Cs can be easily adjusted by the
slope or the angle of the taper portions 29 and the size of the
taper portions 29. The taper portion 29 is formed on the angle
portion of the open face so that the floating capacity Cs may be
obtained.
(Sixteenth Embodiment)
FIG. 34 shows a sixteenth embodiment where the taper portion 29 is
formed on a single side of the dielectric 22. Even in this
embodiment, the floating capacity Cs can be easily obtained by the
taper portion 29.
(Seventeenth Embodiment)
FIG. 35 shows a seventeenth embodiment. In the present embodiment,
a smaller taper or slope portion 29 is formed in a limited portion
instead of along the whole edge or corner of the dielectric 22 as
shown in FIG. 35. In FIG. 35, a slotted portion 30 with a taper
portion 29 being formed therein is formed on only one portion of
the edge of the dielectric 22. Portions 30 may be formed in
plurality on the single side or both the sides of the dielectric
resonator in accordance with the respective holes 23. The number of
the slotted portions 30 is not restricted.
The floating capacity Cs can be easily adjusted by the position and
size of the slotted portions 30.
(Eighteenth Embodiment)
FIG. 36 is an eighteenth embodiment, where a stepped portion 31 of
an approximately L-shape is formed, instead of the taper or slotted
shaped section formed in the previous embodiments, on a corner
portion of a single side on the top face of the dielectric 22. Even
in this case, the distance between the inside conductor 24 within
the hole 23 and the outside conductor 25, which becomes an earth
electrode of the stepped portion 31 is reduced so that the floating
capacity Cs can be easily obtained.
Although the stepped portion 31 is continuously formed along the
edge, as shown in FIG. 36, it may be formed not continuously, in
one portion or intermittent portions, and in the corner portions on
both the side portions of the dielectric 22. The size of the
floating capacity can be easily adjusted by the size and/or the
number of the stepped portions 31.
(Nineteenth Embodiment)
The nineteenth embodiment, shown in FIG. 37, has a stepped portion
31 which is further deepened along the side of the dielectric
resonator as compared with the case of the above described
eighteenth embodiment. In an integrated type of dielectric
resonator, the floating capacity Cs is obtained by the inside
conductor 24, and the stepped portion 31 is formed in a dielectric
filter which is comb-line connected so that the outside conductor
25 is brought closer to the inside conductor 24 within the hole 23
so as to increase the floating capacity Cs.
The approached size W and the depth X of the stepped portion 31 are
adjusted so as to adjust the coupling. When the size of the
dielectric 22 in the axial direction of the hole 23 is made L,
0.ltoreq.X<L.
The coupling coefficients of the dielectric resonator can be
changed by the change in the above described sizes X, W so that the
passing band of the filter can be controlled without changing the
overall shape of the dielectric resonator (metal mold).
The shape of the dielectric resonator can be therefore
standardized, and the metallic cost and the management cost can be
reduced.
As a large coupling coefficient can be obtained without the pitch
between the holes 23 being narrowed, the pole of the high pass
becomes far from the passing band, and the damping of the low pass
is improved. The resonance electrode length becomes shorter with
the floating capacity Cs being increased, so that the filter can be
made smaller in size. Further, a larger filter in the specific band
is obtained.
The dielectric resonator in each of the above described embodiments
is not restricted to the number of the stages shown, although the
three-stage construction has been described. Namely, it can be
applied to a dielectric resonator of one stage or three-stage or
more.
The dielectric resonator of the present invention can be applied to
a case where all the filters such as band pass filter, band
elimination filter, high-pass filter, low-pass filter and so on are
formed.
As is clear from the foregoing description, according to the
arrangement of the present invention, the dielectric resonator of
the present invention can be mounted on the surface of a circuit
basic plate without the use of special individual signal input,
output terminals since the signal input, output electrodes are
provided on the external conductor. Moreover, since the conductor
is formed on the open face of the internal conductor formed hole so
as to eliminate the open face, electromagnetic field leakage is
reduced so that influence by the electromagnetic field leakage is
less if the dielectric resonator is mounted on the circuit basic
plate in a condition as it is.
According to the dielectric resonator of the present invention,
coupling coefficients can be adjusted between the resonator
frequency of the resonator and the resonance without coating
addition and so on by the non-formed portion of the internal
conductor.
According to the dielectric resonator of the present invention, the
open portion of the internal conductor is formed in a location
spaced away from the open face of the internal conductor formed
holes, therefore, the influences by electromagnetic field leakage
is lessened. Therefore, no couplings between the resonator, the
other objects near the resonator and the circuit are provided so
that stable resonator characteristics are provided.
As is clear from the characteristic adjusting method of the
dielectric resonator of the present invention, there are steps of
providing an open portion in one portion of the internal conductor
only by the movement of a grinding tool in the axial direction of
the internal conductor formed hole with the deletion locations of
the internal conductor and the dielectric being restricted. Also,
steps for easily adjusting the tip end capacity by the amount the
grinding tool is moved. Further, a dielectric resonator having
desired resonance frequency and coupling amount can be easily
obtained without demanding higher accuracy in the grinding working
operation, because the tip end capacity is only gradually lowered
in spite of much grinding amount of the whole dielectric.
In a dielectric resonator for making resonant with the desired
frequency by an inside conductor formed on the inside surface of
the hole of the dielectric and an outside conductor formed on the
outside surface of the above described dielectric, a concave or
depressed portion is formed on the surface of the above described
dielectric, the outside conductor of the bottom portion of the
concave or depressed portion is brought closer to the above
described inside conductor so that the distance between the inside
conductor of the hole in the interior of the dielectric and the
outside conductor, which becomes an earth electrode, is reduced so
as to easily obtain the floating capacity by the approaching
operation between the outside conductor at the bottom portion of
the concave or depressed portion formed on the surface of the
dielectric and the above described inside conductor. The floating
capacity can be adjusted by a comparatively simple working or
molding operation of the size, depth and so on of the concave or
depressed portion. In the comb-line type, the band width of the
filter can be made larger by provision of, for example, larger
floating capacity. Resonator length becomes shorter by the
provision of, for example, the larger floating capacity with an
effect that the size may be made smaller.
In the present invention, a taper or sloped portion is formed in
the corner portion of the dielectric, and the outside conductor of
the taper or sloped portion is brought closer to the inside
conductor, the distance between the inside conductor of the hole in
the interior of the dielectric and the outside conductor, which
becomes an earth electrode, is reduced as in the case of the
previous embodiment described above so that the floating capacity
is easier to obtain. The floating capacity can be adjusted by a
comparatively simple working or molding operation of the size,
inclination and so on of the taper or sloped portion of the corner
portion. In the comb-line type, the band width of the filter can be
made larger by the provision of, for example, the larger floating
capacity. The resonator length becomes shorter by provision of, for
example, the larger floating capacity so that the size may be made
smaller.
In the present invention, an approximately L type of stepped
portion in section is provided in the corner portion of the
dielectric, and the outside conductor of the stepped portion is
brought closer to the inside conductor so that the distance between
the inside conductor of the hole in the interior of the dielectric
and the outside conductor, which becomes an earth electrode, is
reduced so as to easily obtain the floating capacity. The floating
capacity can be adjusted by a comparatively simple working or
molding operation of the size, depth and so on of the stepped
portion of the corner portion. In the comb-line type, the band
width of the filter can be widened by provision of, for example,
the larger floating capacity. The resonator length becomes shorter
by provision of, for example, the larger floating capacity so that
the size may be made smaller.
Although the present invention has been fully described by way of
example with reference to the accompanying drawings, it is to be
noted here that various changes and modifications will be apparent
to those skilled in the art. Therefore, unless otherwise such
changes and modifications depart from the scope of the present
invention, they should be construed as included therein.
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